鄂东长江公路大桥宽箱梁C55高性能混凝土试验研究

结合鄂东长江公路大桥边跨预应力混凝土宽箱梁的施工，重点研究了掺入适量矿物掺合料、聚丙烯纤维对箱梁C55高性能混凝土的物理力学性能和长期耐久性的影响。试验结果表明，采用聚羧酸盐高效减水剂，掺入20％Ⅰ级粉煤灰或15％粉煤灰与10％矿粉复掺配制的箱梁C55高性能混凝土具有良好的工作性能、较高的早期强度和较大的后期强度增长，以及很高的抗氯离子渗透性和抗冻性，特别是具有较低水化热温升、较小收缩和徐变变形特性，有利于改善箱梁混凝土的抗裂性。

Experimental Study on C55 High Performance Concrete for Wide Box Girder of Edong Yangtze River Highway Bridge

With reference to the construction of the wide prestressed concrete box girder of boundary span of Edong Yangtze River Highway Bridge, the effects of incorporating appropriate amount of mineral admixtures and polypropylene fiber （PP） on physical and mechanical performances and durability of the C55 high performance （HPC） of box girder are investigated mainly. The test results show that the C55 HPCS, adopting a retarding-type polyearboxyhe-aeid high-range water reducer and incorporating with 20% fly ash （FA） or the composites of 15% FA and 10% granulated blaster furnace slag （GBFS） , have good workability, high early strength and large increment of later strength. Moreover, the C55 HPCS have high resistance to chloride ion penetration and advanced freezing and thawing resistance, especially the characteristics such as their low hydration heat temperature rise and less deformations of dry shrinkage and creep are favorable for improving the resistance to crack of the box girder concrete.